The precursor of the thegn was the gesith, the companion of the king or great lord, the member of his comitatus, and the word thegn began to be used to describe a military gesith.
The thegn became a member of a territorial nobility, and the dignity of thegnhood was attainable by those who fulfilled certain conditions.
A king's thegn was a person of great importance, the contemporary idea being shown by the Latin translation of the words as comes.
No one save the king had the right of jurisdiction over him, while by a law of Canute we learn that he paid a larger heriot than an ordinary thegn.
The eorl of the old system would doubtless commonly become a thegn under the new, as the Roman patrician took his place in the new nobilitas; but others could take their place there also.